Aeroplane hatch coaming



R. J. DAVIS ET AL AEHOPLANE HATCH COAMING Filed June 13, 1931 lrifors 4 Patented Aug. 25, 1931 UNITED STATES ROY J. DAVIS annenonoenl waters, or PORTLAND, onneon AEROPLANE Heron COAMING F Application fi1ed June 13,

Our invention relates to coamings fitted about the aperture in the fuselage through -Which access is had to the cockpit, the same h serving as a fending and resilient padding 6 sheathing the marginal edge of the fuselage structure, and particularly toa special composition and form thereof of desirable aerodynamic characteristics adaptable universally to the varying figures and curves of the openings of the several models.

The principal object of our invention is to provide a standard coaming having all of the desirable characteristics of such a fitting in an enhanced degree capable of quick and'easy E315 attachment.

A second object is to providefor an enhanced durability of the 'coaming.

. A third object is to facilitate the manufacture of the coaming and henceprov-ide for 7 an improved quality and lesser cost.

Other objects and advantages of our invention will be apparent in the following discourse wherein the significance of the reference characters in the accompanying drawings, details of construction of a typical coaming embodying our-invention,,and the particular advantages thereof are explained.

Figure 1 represents a view of the side of a fragment of an aeroplane fuselage fitted with the hatch coaming of my invention.

Figure 2 represents a view of a transverse section: of the coaming as manufactured.

Figure 3 represents a view of a length of the coaming as manufactured. 7

Figure 4 is a diagram representative of the cross-sectional figure of the coaming when applied to the fuselage, a fragment of the latter being shownin section. v

Figure 5 is a diagram illustrat-iveof .c'ertain effects described further on.

Our invention consistsin the particula form and combination of materials of a standard design and construction adapted for manufacture in continuous lengths.

The coaming is composedof a continuous, length of resilient material as sponge-rubber of the uniform sectional form illustrated in Figure .2 where the sponge-rubber body is indicated by the numeral 1. The spongefied hydraulicity as well as resilience. accordance with the laws governlng bending rubber body is encased in an adhering fabric-z 1931. Serial No. 544,160.

covering 2, the edges of which are disposed within the tapered groove A of the form shown. As manufactured, a length of the coaming is straight as shown in Figure 3.

Upon application to the fuselage involving 1 the bending of the coaming to conform to the curves of the edge covered, the normal cross-sectional figure of the coaming as illustrated in Figure 2 is distorted to that form illustrated in Figure 4 where it will be observed that the groove is of rectangular section. A virtually perfect adaptation of the coaming to the fuselage is thus effected.

In detail this adaptation accrues out of these following properties of the materials. employed as related to the effects of distorting the normally straight length, of coaming with normally tapering groove to the irregularly curved figure of the fuselage edge:

The fabric covering 2 is susceptible of great compression in its linear dimensions and of relatively little extension thereof. The sponge-rubber body is possessed of a modi- 7 strains, the sponge-rubber body of the 00amingtends to bend about a neutral axis disposed medially of its cross-sectional extremities as determined by the moments in" volved, and in natural course-that portion lying nearestthe center of curvature will be compressed and that portion most remotely situated therefrom will be strained in tension. V r In bodies of symmetrical section these strains are productive of forces tending to distort the cross-sectional figure of the body in amanner to decrease that dimension thereof measured in the plane of curvature and to increase that dimension perpendicular thereto. But in the coaming of my invention the compressive strains in that portion lying IlGflIGSlL the center Of curvature 2116 C0111H111I1lcated to the portions most remote therefrom,

and, since the tapered grooves provides a voidin this latter. portion, these strains are resolved into forces and hence movements thereof effecting the narrowing of the groove. 1

Itwillhe quite apparent that after the void .face of improved aerodynamic characterisprovided by the groove is filled either by the movement of the groove walls toward each other or by the fuselage structure, or the combination or both, further strains will tend to distort the coaming so as to increase the dimension thereof perpendicular to the plane of curvature Now, such: further straining is contemplated in my invention to provide for a liberal range of variation tactwith the fuselage structure. S'uclr compression in length is practicable in the application" of the coamingand' facilitates the making of butt joints. This is in distinct contrast to the method of' drawing a covering material over a stuffing and securing the former to the fuselage structure at intervals. In the coaming of my invention the edges of the lips are forced into contact with the fuselage structure at every point regardless of. the manner of securing the same thereupon, thusprovidlng a fair and smooth surtics.

The fabric covering provides further effects contributing to the total mechanical effects thus produced as well as affording a surface adapted to finishing in any desired manner. The warp of the fabric is disposed parallel with the length of the coaming in its manufacture, providing for the disposition of the transverse yarns in a manner to be strained in tension during the distortion of the coaming to fit the particular fuselage to which it is attached. Thus, since the figure of the section is approximately circular in one part, the compression of the spongerubber body will be adequately contained'a'nd the pressure so developed in bending will be communicated to the extended portions. On the other hand the warp yarns disposed at the greatest radius from the center of curvature will tend to constrain the lips of the coaming into close contact with the fuselage in View of the location of the center ofresistance of the sponge-rubber body to-this centripetal action of these yarns strained in tension.

In addition to these effects the fabric cov- 7 ering provides for the convenient riveting of the coaming to the fuselage structure, as indicated at 3' in Figure 4, to insure agamst accidental displacement.

In the course of time after the coaming of 7 our invention is applied to the aeroplane'it assumes a permanent set and the strains are more or less equalized so that eventually, a

coaming thus applied becomes ideally adapted to the figure of the fuselage edges.

The advantages of the coaming of our invention will be readily apparent to the aviator and manufacturer.

Having described our invention what we claim is: V M I 1'. The method of forminghatch coaming for aeroplanes consisting in the forming of a length of fabric covered resilient ma- 7 terial' of such normal uniform cross section as described characterized by a tapered groove and the subsequent bending thereof to conform to the-figure of the edge to which it is applied to effect the closure of the said tapered groove to make substantial contact with the fuselage structure".

2- An aeroplane. hatch coaming. of. resilient material. and. of normally straight form and of uniform cross: section charac- 3 terized by a circular portion and twosymmetrical: extending lips forming therebetween a normally tapered groove.

3'. Aeroplane hatch coaming comprising indeterminate lengths of normally straight resilient material of the uniform cross-sectional figure characterized by a circular; portion and extended lips embracing a tapered groove.

4. Aeroplane hatch coaming in indeter minate continuous lengths. of normally straight form, resilient composition, and the uniform cross-sectional. figure characterized by a circular portion. and-fextended lips embracing a: normally tapered groove adapted to engage the fuselage structure when the coaming is'hent to: the curves of the fuselage edge.

5. Aeroplane hatch coaming consisting of a normallystraight' resilient body of the uniform cross-sectional figure characterized by a circular portion and extended lips: embracing a normally tapered groove adapted to engage the edge of the fuselage structure whenbent thereto, the same being. cove'red with adhering fabric whose warp. is disposed parallel to the length of the coamingv and whose edges are disposed within said' normally taperedigroove. a

6; Aeroplane hatch coaming consisting 05 normally straight continuouslengths of elastic resilient. material of the cross-sectional figure characterized by an approirimately circular portion and extended lips embracing a normally tapered groove adapted: 1:0" engage the edge of the fuselage structure when bent thereto, the same'being' covered with a: fabric'whose warp is disposed parallel to the lengthofthe coaming and whose edges are disposed within said normally taperetF groove.v .1 ROY J. DAVIS. GEORGE E; WATTS! 

